Former Labor Secretary Hilda Solis speaks at the National Press Club in Washington in August 2011. (AP Photo/Manuel Balce Ceneta)

Former Labor Secretary Hilda Solis regularly flew on a private jet owned by the International Union of Operating Engineers while she served in Congress but failed to disclose the travel in her financial filings, a violation of House gift rules, according to a recent lawsuit. The travel included the period after she was nominated by President Obama in 2009 to serve in his cabinet.

The allegation is included in a lawsuit filed by members of IUOE Local 12 against IUOE First Vice President William Waggoner, his immediate family and other top union officials. The Los Cerritos (Calif.) News says it has independently confirmed that Solis was provided with "thousands" of dollars worth of flight time on the local's Cessna Citation Excel jet.

Solis is not a defendant in the class action lawsuit, which alleges that Waggoner embezzled union funds. The suit alleges that Waggoner "bragged openly that he was flying Solis back to Washington, D.C." from her home in El Monte, Calif.

IUOE and Solis have long had close ties, the union having backed her congressional campaigns as well as when she served in local government. She has received at least $900,000 in reported contributions from the union. She represented California's 32nd Congressional District from 2003 through 2009.

The News reports that Waggoner may have gotten special consideration after Solis was confirmed as labor secretary: "According to the lawsuit, in late 2012, Waggoner flew union leaders Larry Hopkins and Ron Havlick to Washington, D.C., 'to meet with Ms. Solis over a Local 12 problem involving the Department of Labor when Waggoner believed that legal action was imminent.'"